CHESS THE strange history of man-vs.-machine matches took a new turn earlier this month when Jaan Ehlvest tried for revenge against Rybka but received a strange type of odds.

Since Garry Kasparov was humiliated by Deep Blue 10 years ago, organizers of computer matches have tried to “level the playing field” by eliminating a machine’s allegedly unfair advantages, such as its opening “book” knowledge, which often runs more than 25 moves deep.

But the machines kept winning. So, in the first Ehlvest-vs.-Rybka match in March, the world champion gave odds – one pawn in each game. It won 51/2-21/2.

Fans of humanity found an excuse: Ehlvest, once the world’s fifth-highest rated human, is used to non-odds games, they said. He was the one at a handicap because he was forced into wholly unfamiliar positions against Rybka (!).

So in Round 2, Ehlvest got new advantages. He played White in every game and had twice as much time as the machine. Most important of all, Rybka’s opening “book” beyond the third move was wiped out.

In this week’s game, for example, the machine was on its own after 3 . . . Qd6. There are virtual beginners who have more opening knowledge than this.

It didn’t matter. Rybka simply outplayed Ehlvest again in middlegames and finished off 41/2-11/2.

BRIDGE THE PGA Tour keeps a player’s “bounceback” statistics: how he responds to adversity. When he makes a bogey, does he recover with a birdie or let one bad hole breed more?

Even the best bridge players have disasters, and it takes character to make the best of a bad situation.

In today’s deal, North-South were nailed by East-West preemption. When East opened three hearts, South could have doubled but overcalled three spades instead. Then West’s gentle lift to four hearts was just right, since it prevented North from showing his clubs comfortably. With few options, North tried four spades. And everyone passed.

West led a heart, and when South saw dummy, he was so disgusted at missing the cold seven clubs that he forgot to make four spades. He ruffed the first heart, led a trump to the king and returned a trump.

When East discarded, South started the clubs. West, who had more trumps than South, ruffed the second club and plugged away at hearts, and South, who had lost trump control at the first trick, had to go down.

In case trumps break 5-1, South should discard a diamond on the first heart and another diamond if East continues with the ace of hearts. If East leads a third heart, South can ruff in dummy, cash the king of trumps, lead a club to his hand, take the A-Q-J of trumps and run the clubs, losing only to West’s high trump.

How are your “bounceback” stats? You’d be forgiven for missing seven clubs – few pairs would reach that contract – but would you make four spades?